This latest video rendering from from Analytical Graphics, Inc. (AGI) shows ROSAT’s current orbit, the satellite’s ground track, and the estimated model of the break-up and debris scattering. Deutsches Zentrum für Luft- und Raumfahrt (DLR), the German Space Agency has now refined the re-entry to sometime between October 22 and 23, 2011, plus or minus one day. DLR says this slot of uncertainty will be reduced as the date of re-entry approaches. However, even one day before re-entry, the estimate will only be accurate to within plus/minus five hours.
The orbit extends from 53 degrees northern and southern latitude, and all areas in that region could be affected by its re-entry. The bulk of the debris will impact near the ground track of the satellite, but larger parts of the satellite, including its 32 inch, 400 kg mirror, could fall to Earth in a 80-kilometer-wide path along the track.
Update: A report from the ROSAT_Renetry Twitter feed posted at 18:00 UT on October 20 said they expect re-entry in 64 hours. “ROSAT orbit 88.58 minutes 196.8 x 201.7 km, Position 26.6S,164.0W alt=203.2km Lit ~Re-entry 64 hours”
We’ll provide more updates as they become available. You can check the DLR ROSAT webpage for more updates.
Scientists leading NASA’sDawn mission have discovered a 2nd giant impact basin at the south pole of the giant asteroid Vesta, which has been unveiled as a surprisingly “dichotomous” and alien world. Furthermore, the cosmic collisions that produced these two basins shuddered through the interior and created vast Vestan troughs, a Dawn scientist told Universe Today.
The newly discovered impact basin, nicknamed ‘Older Basin’, is actually significantly older in age compared to the initially discovered South Pole basin feature named ‘Rheasilvia’ – perhaps by more than a billion years. And that is just one of the many unexplained mysteries yet to be reconciled by the team as they begin to sift through the millions of bits of new data streaming back daily to Earth.
Scientists speculate that ‘Older Basin’ is on the order of 3.8 Billion years old, whereas ‘Rheasilvia’ might be as young as about 2.5 Billion years, but those are just tentative estimates at this time and subject to change. Measurements so far indicate Rheasilvia is composed of basaltic material.
“We found many surprising things at Vesta, which is quite unique and the results have exceeded our expectations”, said Dr. Carol Raymond, Dawn deputy principal investigator, of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
Researchers presented the latest findings from Dawn’s initial science mapping orbit at a news briefing at the annual meeting of the Geological Society of America in Minneapolis, Minn., on Oct. 13.
The team considers Vesta to be the smallest terrestrial planet.
Since achieving orbit in July, Dawn’s Framing Cameras (FC) have imaged most of Vesta at about 250 meter resolution and the Visible and Infrared mapping spectrometer(VIR) at about 700 meter resolution. The measurements were collected at the survey orbit altitude of 2700 km. Before Dawn, Vesta was just a fuzzy blob in humankind’s most powerful telescopes.
“There is a global dichotomy on Vesta and a fundamental difference between the northern and southern hemispheres”, said Raymond. “The northern hemisphere is older and heavily cratered in contrast to the brighter southern hemisphere where the texture is more smooth and there are lots of sets of grooves. There is a massive mountain at the South Pole. One of the more surprising aspects is the set of deep equatorial troughs.”
“There is also a tremendous and surprising diversity of surface color and morphology. The south is consistent with basaltic lithology and the north with impacts. We are trying to make sense of the data and will integrate that with the high resolution observations we are now collecting.”
Indeed Vesta’s completely unique and striking dichotomy can be directly traced back to the basins which were formed by ancient cataclysmic impacts resulting in shockwaves that fundamentally altered the surface and caused the formation of the long troughs that ring Vesta at numerous latitudes.
“The troughs extend across 240 degrees of longitude,” said Debra Buczkowski, Dawn participating scientist, of the Applied Physics Laboratory at Johns Hopkins University, Laurel, Md. “Their formation can be tied back to the two basins at the South Pole.”
In an exclusive follow up interview with Universe Today, Raymond said “We believe that the troughs formed as a direct result of the impacts,” said “The two sets of troughs are associated with the two large basins [Rheasilvia and Older Basin].”
“The key piece of evidence presented was that the set of troughs in the northern hemisphere, that look older (more degraded) are circumferential to the older impact basin,” Raymond told me.
“The equatorial set are circumferential to Rheasilvia. That Rheasilvia’s age appears in places to be much younger is at odds with the age of the equatorial troughs. An explanation for that could be resurfacing by younger mass wasting features (landslides, slumps). We will be working on clarifying all these relationships in the coming months with the higher resolution HAMO (High Altitude Mapping Orbit) data.”
Dawn has gradually spiraled down closer to Vesta using her exotic ion thrusters and began the HAMO mapping campaign on Sept. 29.
Surface features are dated by crater counting methodology.
“Preliminary crater counting age dates for the equatorial trough region yields a very old age (3.8 Billion years). So there is a discrepancy between the apparent younger age for the Rheasilvia basin and the old age for the troughs. These could be reconciled if Rheasilvia is also 3.8 Billion years old but the surface has been modified by slumping or other processes,” Raymond elaborated.
Time will tell as further data is analyzed.
“Vesta is full of surprises, no more so than at the South Pole,” said Paul Schenk at the GSA briefing. Schenk is a Dawn participating scientist of the Lunar and Planetary Institute, Houston, Texas.
The ‘Rheasilvia’ basin was initially discovered in images of Vesta taken a decade ago by the Hubble Space Telescope which revealed it as a gaping hole in the southern hemisphere. But it wasn’t until Dawn entered orbit on July 16, 2011 after a nearly four year interplanetary journey that Earthlings got their first close up look at the mysterious polar feature and can now scrutinize it in detail to elucidate its true nature.
“The South Pole [Rheasilvia] basin is a roughly circular, impact structure and a deep depression dominated by a large central mound,” said Schenk. “It shows sharp scarps, smooth areas, landslide deposits, debris flows. It’s about 475 km in diameter and one of the deepest (ca. 20 -25 km) impact craters in the solar system.”
The central peak is an enormous mountain, about 22 km high and 180 km across- one of the biggest in the solar system. “It’s comparable in some ways to Olympus Mons on Mars,” Schenk stated.
“We were quite surprised to see a second basin in the mapping data outside of Rheasilvia. This was unexpected. It’s called ‘Older Basin’ for now.”
‘Older Basin’ is about 375 km in diameter. They overlap at the place where Rheasilvia has a missing rim.
“These basins are interesting because we believe Vesta is the source of a large number of meteorites, the HED meteorites that have a spread of ages,” Schenk explained.
Multiple large impacts over time may explain the source of the HED (Howardite, Eucrite and Diogenite) meteorites.
“We did expect large impacts on Vesta, likely associated with the late heavy bombardment recognized in the lunar impact record,” Raymond told Universe Today. “The surprising element is that the two apparently largest impacts – keeping in mind that other larger impact basins may be lurking under the regolith – are overlapping.”
Dawn’s VIR spectrometer has detected pyroxene bands covering Vesta’s surface, which is indicative of typical basaltic material, said Federico Tosi, a VIR team member of the Italian Space Agency, Rome. “Vesta has diverse rock types on its surface.”
“VIR measured surface temperatures from 220K to 270 K at the 5 micron wavelength. The illuminated areas are warmer.”
So far there is no clear indication of olivine which would be a marker for seeing Vesta’s mantle, Tossi elaborated.
The VIR spectrometer combines images, spectral information and temperature that will allow researchers to evaluate the nature, composition and evolutionary forces that shaped Vesta’s surface.
The team is absolutely thrilled to see a complicated geologic record that’s been preserved for study with lots of apparent surface layering and surprisingly strong and complex structural features with a large range of color and brightness.
Try not to plummet off a steep crater cliff or be buried under a landslide while gazing at the irresistibly alluring curves of beautiful Rheasilvia – the mythical mother of Romulus and Remus – whose found a new home at the South Pole of the giant Asteroid Vesta.
3 D is undoubtedly the best way to maximize your pleasure. So whip out your cool red-cyan anaglyph glasses to enhance your viewing experience of Rheasilvia, the Snowman and more – and maximize your enjoyment of this new 3 D collection showcasing the heavily cratered, pockmarked, mountainous and groovy terrain replete at Vesta.
Scientists and mortals have been fascinated by the enormous impact crater Rheasilvia and central mountain unveiled in detail by NASA’s Dawn Asteroid Orbiter recently arrived at Vesta, the 2nd most massive object in the main asteroid belt. Ceres is the largest object and will be Dawn’s next orbital target in 2015 after departing Vesta in 2012.
“Vesta is the smallest terrestrial planet in our Solar System”, said Chris Russell in an interview with Universe Today. “We do not have a good analog to Vesta anywhere else in the Solar System.”
And the best is yet to come. In a few days, Dawn begins snapping images from a much lower altitude at the HAMO mapping orbit of ca. 685 km vs the initial survey orbit of ca, 2700 km. where most of these images were taken.
Can you find the location of the 3 D South Pole images above in the 2 D South Pole image below?
Read Ken’s continuing features about Dawn and Vesta
Video caption: Rheasilvia Impact Basin and Vesta shape model. This false-color shape model video of the giant asteroid Vesta was created from images taken by the framing camera aboard NASA’s Dawn spacecraft. Rheasilvia – South Pole Impact Basin – shown at bottom (left) and head on (at right). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
‘Rheasilvia’ – that’s the brand new name given to the humongous and ever more mysterious South Pole basin feature being scrutinized in detail by Dawn, according to the missions top scientists in a Universe Today exclusive. Dawn is NASA’s newly arrived science orbiter unveiling the giant asteroid Vesta – a marvelously intriguing body unlike any other in our Solar System.
What is Rheasilvia? An impact basin? A crater remnant? Tectonic action? A leftover from internal processes? Or something completely different? That’s the hotly debated central question consuming loads of attention and sparking significant speculation amongst Dawn’s happily puzzled international science team. There is nothing closely analogous to Vesta and Rhea Silvia – and thats a planetary scientists dream come true.
“Rheasilvia – One thing that we all agree on is that the large crater should be named ‘Rheasilvia’ after the mother of Romulus and Remus, the mythical mother of the Vestals,” said Prof. Chris Russell, Dawns lead scientist, in an exclusive interview with Universe Today. Russell, from UCLA, is the scientific Principal Investigator for Dawn.
“Since we have never seen any crater just like this one it is difficult for us to decide exactly what did happen,” Russell told me. “The name ‘Rheasilvia’ has been approved by the IAU and the science team is using it.”
Craters on Vesta are being named after the Vestal Virgins—the priestesses of the Roman goddess Vesta. Other features will be named for festivals and towns of that era. Romulus and Remus were the mythical founders of Rome.
‘Rheasilvia’ has the science team in a quandary, rather puzzled and reevaluating and debating long held theories as they collect reams of new data from Dawn’s three science instruments – provided by the US, Germany and Italy. That’s the scientific method in progress and it will take time to reach a consensus.
Prior to Dawn’s orbital insertion in July 2011, the best views of Vesta were captured by the Hubble Space Telescope and clearly showed it wasn’t round. Scientists interpreted the data as showing that Vesta’s southern hemisphere lacked a South Pole! And, that it had been blasted away eons ago by a gargantuan cosmic collision that excavated huge amounts of material that nearly utterly destroyed the asteroid.
The ancient collision left behind a colossal 300 mile (500 km) diameter and circular gaping hole in the southern hemisphere – nearly as wide as the entire asteroid (530 km) and leaving behind an as yet unexplained and enormous central mountain peak, measuring some 9 miles (15 km) high and over 125 miles (200 km) in diameter. The mountain has one of the highest elevations in the entire solar system.
“We are trying to understand the high scarps that we see and the scarps that should be there and aren’t,” Russell explained. “We are trying to understand the landslides we think we see and why the land slid. We see grooves in the floor of the basin and want to interpret them.
“And the hill in the center of the crater remains as mysterious today as when we first arrived.”
Another top Dawn scientist described Rheasilvia in this way:
“I would say that the floor of the impact feature contains chaotic terrain with multiple sets of intersecting grooves, sometimes fairly straight and often curvy, said Carol Raymond to Universe Today. Raymond is Dawn’s Deputy Principal Investigator from NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“The crater rim is not well-expressed”, Raymond told me. “We see strong color variations across Vesta, and the south pole impact basin appears to have a distinct spectral signature.
“The analysis is still ongoing,” Russell said.
“The south is distinctly different than the north. The north has a varied spectrum and the south has a distinct spectral feature but it has little variation.” Time will tell as additional high resolution measurements are collected from the forthcoming science campaign at lower orbits.
Russell further informed that the team is rushing to pull all the currently available data together in time for a science conference and public briefing in mid-October.
“We have set ourselves a target to gather everything we know about the south pole impact feature and expect to have a press release from what ever we conclude at the GSA (Geological Society of America) meeting on October 12. “We will tell the public what the options are.”
“We do not have a good analog to Vesta anywhere else in the Solar System and we’ll be studying it very intently.”
Right now Dawn is using its ion propulsion system to spiral down four times closer to Vesta, as it descends from the initlal survey orbit(about 2700 km, 1700 mi) to the new science orbit, elegantly named HAMO – or High Altitude Mapping Orbit (about 685 km.)
“Our current plan is to begin HAMO on Sept. 29, but we will not finalize that plan until next week,” Dr. Marc Rayman told Universe Today. Rayman, of NASA’s JPL, is Dawn’s Chief Engineer.
“Dawn’s mean altitude today (Sept. 20) is around 680 km (420 miles),” said Rayman .
“Dawn successfully completed the majority of the planned ion thrusting needed to reach its new science orbit and navigators are now measuring its orbital parameters precisely so they can design a final maneuver to ensure the spacecraft is in just the orbit needed to begin its intensive mapping observations next week.”
Watch for lots more stories upcoming on Vesta and the Dawn mission
The Dawn science team has released two spectacular rotation movies of the entire globe of the giant asteroid Vesta. The flyover videos give the distinct impression that you are standing on the bridge of the Starship Enterprise and gazing at the view screen as the ship enters orbit about a new planet for the first time and are about to begin an exciting new journey of exploration and discovery of the body you’re looking at below.
Thanks to NASA, DLR, ASI and Dawn’s international science and engineering team, we can all join the away team on the expedition to unveil Vesta’s alluring secrets.
Click the start button and watch protoplanet Vesta’s striking surface moving beneath from the perspective of Dawn flying above – in the initial survey orbit at an altitude of 2700 kilometers (1700 miles). Vesta is the second most massive object in the main asteroid belt and Dawn’s first scientific conquest.
Another video below was compiled from images taken earlier on July 24, 2011 from a higher altitude after Dawn first achieved orbit about Vesta and revealed that the northern and southern hemispheres are totally different.
The array of images in the videos was snapped by Dawn’s framing camera which was provided by the German Aerospace Center (DLR). The team then created a shape model from the images, according to Dr. Carol Raymond, Dawn’s Deputy Principal Investigator from NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The shape model will aid in studying Vesta’s strikingly diverse features of mountains, ridges, valley’s, scarps, cliffs, grooves, craters, even a ‘snowman’ and much more.
Notice that not all of Vesta is illuminated – because it’s northern winter at the asteroid. Vesta has seasons like Earth and the northern polar region in now in perpetual darkness. Data is collected over the day side and radioed back to Earth over the night side.
“On Vesta right now, the southern hemisphere is facing the sun, so everywhere between about 52 degrees north latitude and the north pole is in a long night,” says Dr. Rayman, Dawn’s Chief Engineer from JPL. “That ten percent of the surface is presently impossible to see. Because Dawn will stay in orbit around Vesta as together they travel around the sun, in 2012 it will be able to see some of this hidden scenery as the seasons advance.”
Another movie highlight is a thorough look at the gigantic south pole impact basin. The circular feature is several hundred miles wide and may have been created by a cosmic collision eons ago that excavated massive quantities of material and basically left Vesta lacking a south pole.
The massive feature was discovered in images taken by the Hubble Space Telescope several years ago and mission scientists have been eager to study it up close in a way that’s only possible from orbit. Dawn’s three science instruments will investigate the south pole depression in detail by collecting high resolution images and spectra which may reveal the interior composition of Vesta.
Dawn entered the survey orbit on Aug. 11 and completed seven revolutions of 69 hours each on Sept. 1. It transmitted more than 2,800 pictures from the DLR framing camera covering the entire illuminated surface and also collected over three million visible and infrared spectra from the VIR spectrometer – provided by ASI, the Italian Space Agency. This results exceeded the mission objectives.
The Dawn spacecraft is now spiraling down closer using its ion propulsion system to the next mapping orbit – known as HAMO – four times closer than the survey orbit and only some 680 km (420 miles) above the surface.
NASA has just released the first full frame images of Vesta– and they are thrilling! The new images unveil Vesta as a real world with extraordinarily varied surface details and in crispy clear high resolution for the first time in human history.
Vesta appears totally alien and completely unique. “It is one of the last major uncharted worlds in our solar system,” says Dr. Marc Rayman, Dawn’s chief engineer and mission manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Now that we are in orbit we can see that it’s a unique and fascinating place.”
“We have been calling Vesta the smallest terrestrial planet,” said Chris Russell, Dawn’s principal investigator at the UCLA. “The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta’s planetary aspirations.”
The newly published image (shown above) was taken at a distance of 3,200 miles (5,200 kilometers) by Dawn’s framing camera as the probe continues spiraling down to her initial science survey orbit of some 1,700 miles (2,700 km) altitude. The new images show the entire globe all the way since the giant asteroid turns on its axis once every five hours and 20 minutes.
Vesta and its new moon – Dawn – are approximately 114 million miles (184 million kilometers) distant away from Earth.
“The new observations of Vesta are an inspirational reminder of the wonders unveiled through ongoing exploration of our solar system,” said Jim Green, planetary division director at NASA Headquarters in Washington.
Dawn was launched atop a Delta II Heavy booster rocket in September 2007, took a gravity assist as it flew past Mars and has been thrusting with exotic ion propulsion for about 70 percent of the time ever since.
Dawn will spend 1 year collecting science data in orbit around Vesta before heading off to the Dwarf Planet Ceres.
The science team has just completed their press briefing. Watch for my more detailed report upcoming soon.
And don’t forget JUNO launches on Aug 5 – It’s an exciting week for NASA Space Science and I’ll be reporting on the Jupiter orbiter’s blastoff and more – as Opportunity closes in on Spirit Point !
NASA’s groundbreaking interplanetary science is all inter connected – because Vesta and Ceres failed to form into full-fledged planets thanks to the disruptive influence of Jupiter.
NASA’s super exciting Dawn mission to the Asteroid Belt marked a major milestone in human history by becoming the first ever spacecraft from Planet Earth to achieve orbit around a Protoplanet – Vesta – on July 16. Dawn was launched in September 2007 and was 117 million miles (188 million km) distant from Earth as it was captured by Asteroid Vesta.
Dawn’s achievements thus far have already exceeded the wildest expectations of the science and engineering teams, and the adventure has only just begun ! – so say Dawn’s Science Principal Investigator Prof. Chris Russell, Chief Engineer Dr. Marc Rayman (think Scotty !) and NASA’s Planetary Science Director Jim Green in exclusive new interviews with Universe Today.
As you read these words, Dawn is steadily unveiling new Vesta vistas never before seen by a human being – and in ever higher resolution. And it’s only made possible via the revolutionary and exotic ion propulsion thrusters propelling Dawn through space (think Star Trek !). That’s what NASA, science and space exploration are all about.
“Dawn is in orbit, remains in good health and is continuing to perform all of its functions,” Marc Rayman of the Jet Propulsion Laboratory, Pasadena, Calif., told me. “Indeed, that is how we know it achieved orbit. The confirmation received in a routine communications session that it has continued thrusting is all we needed.”
Dawn entered orbit at about 9900 miles (16000 km) altitude after a nearly 4 year journey of 1.73 billion miles.
Over the next few weeks, the spacecrafts primary task is to gradually spiral down to its initial science operations orbit, approximately 1700 miles above the pock marked surface.
Vesta is the second most massive object in the main Asteroid Belt between Mars and Jupiter. Dawn is the first probe to orbit an object in the Asteroid Belt.
I asked Principal Investigator Chris Russell from UCLA for a status update on Dawn and to describe what the team can conclude from the images and data collected thus far.
“The Dawn team is really, really excited right now,” Russell replied.
“This is what we have been planning now for over a decade and to finally be in orbit around our first ‘protoplanet’ is fantastic.”
“The images exceed my wildest dreams. The terrain both shows the stress on the Vestan surface exerted by 4.5 billion years of collisions while preserving evidence [it seems] of what may be internal processes. The result is a complex surface that is very interesting and should be very scientifically productive.”
“The team is looking at our low resolution images and trying to make preliminary assessments but the final answers await the higher resolution data that is still to come.”
Russell praised the team and described how well the spacecraft was operating.
“The flight team has been great on this project and deserves a lot of credit for getting us to Vesta EARLY and giving us much more observation time than we had planned,” Russell told me.
“And they have kept the spacecraft healthy and the instruments safe. Now we are ready to work in earnest on our science observations.”
Dawn will remain in orbit at Vesta for one year. Then it will fire its ion thrusters and head for the Dwarf Planet Ceres – the largest object in the Asteroid Belt. Dawn will then achieve another major milestone and become the first spacecraft ever to orbit two celestial objects.
Jim Green, Director of Planetary Science for the Science Mission Directorate (SMD) at NASA HQ in Washington, DC, summed up his feelings about Dawn in this way;
“Getting Dawn into orbit is an amazing achievement,” Green told me.
“Instead of the ‘fire the thrusters full blast’ we just sort of slid into orbit letting gravity grab the spacecraft with a light tug. This gives us great confidence that the big challenge down the road of getting into orbit around Ceres can also be accomplished just as easily.”
Sharper new images from Vesta will be published by NASA in the next day or so.
“We did take a few navigation images in this last sequence and when they get through processing they should be put on the web this week,” Russell informed. “These images are from a similar angle to the last set and with somewhat better resolution and will not reveal much new.”
However, since Dawn is now orbiting Vesta our upcoming view of the protoplanet will be quite different from what we’ve seen in the approach images thus far.
“We will be changing views in the future as the spacecraft begins to climb into its science orbit,” stated Russell.
“This may reveal new features on the surface as well as giving us better resolution. So stay tuned.”
Marc Rayman explained how and why Dawn’s trajectory is changing from equatorial to polar:
“Now that we are close enough to Vesta for its gravity to cause a significant curvature in the trajectory, our view is beginning to change,” said Rayman. “That will be evident in the pictures taken now and in the near future, as the spacecraft arcs north over the dark side and then orbits back to the south over the illuminated side.”
“The sun is over the southern hemisphere right now,” added Russell. “When we leave we are hoping to see it shine in the north.”
Dawn is an international mission with significant participation from Germany and Italy. The navigation images were taken by Dawn’s framing cameras which were built in Germany.
Exploring Vesta is like studying a fossil from the distant past that will immeasurably increase our knowledge of the beginnings of our solar system and how it evolved over time.
Vesta suffered a cosmic collision at the south pole in the distant past that Dawn can now study at close range.
“For now we are viewing a fantastic asteroid, seeing it up close as we zero in on its southern hemisphere, looking at the huge central peak, and wondering how it got there,” explained Jim Green
“We know Vesta was nearly spherical at one time. Then a collision in its southern hemisphere occurred blowing off an enormous amount of material where a central peak now remains.”
That intriguing peak is now obvious in the latest Dawn images from Vesta. But what does it mean and reveal ?
“We wonder what is that peak? replied Green. “Is it part of the core exposed?
“Was it formed as a result of the impact or did it arise from volcanic action?”
“The Dawn team hopes to answer these questions. I can’t wait!” Green told me.
As a result of that ancient south pole collision, about 5% of all the meteorites found on Earth actually originate from Vesta.
Keep your eyes glued to Dawn as mysterious Vesta’s alluring secrets are unveiled.